猕猴桃果酒发酵条件优化及其抗氧化特性研究

目的 研究猕猴桃果酒的最优发酵工艺参数及其抗氧化特性。方法 以黄心猕猴桃为原料,采用单因素试验和响应面Box-Behnken试验设计优化了猕猴桃果酒的发酵工艺参数。分析了陈酿期间黄心猕猴桃果酒在不同陈酿温度和时间下,酒体中总酚含量与体外抗氧化活性之间的关系。结果 猕猴桃果酒最佳工艺条件为:发酵温度22.07℃,初始糖度为22.58?Brix,酵母接种量0.13%。在此条件下,酒精度可达8.94%vol。在果酒陈酿期间,随着陈酿时间的延长,黄心猕猴桃果酒的抗氧化能力和酚类物质含量均有所降低。相同陈酿时间下, 4℃下陈酿的黄心猕猴桃果酒的体外抗氧化能力高于18℃陈酿的猕猴桃果酒。结论 本研究结果对实际生产上猕猴桃果酒的加工有参考指导作用。酚类物质的变化与其体外抗氧化能力呈现出正相关,这也表明酚类物质可能对猕猴桃果酒体外抗氧化能力起主导作用。     

The influence of malt and wort processing on spirit character: the lost styles of Scotch malt whisky

Over the last 50 years there has been considerable analytical research on the malt parameters which govern the flavour and aroma, i.e. the ‘character’, of Scotch malt whisky. This has led to a standard format, the Flavour Wheel, to describe the attributes of any malt spirit and to relate them to a common group of malt parameters. What has not been well documented in the same period are the changes in malt processing technology which have led to a gradual but significant change in the concentrations of reference compounds used in the Flavour Wheel relating to sulphury, nutty/burnt/smoky, peaty and fruity/estery characters. This review covers the most significant of these changes, which have become common practice across the industry, and specifically demonstrates how different malting barley varieties, malt kilning and peating, wort recovery, yeast management, and wash still heating have all contributed to the loss of some styles of malt whisky. © 2019 The Institute of Brewing & Distilling     

遮光处理对赤霞珠非花色苷酚组分及含量的影响

选取昌吉遗韵酒庄酿酒葡萄赤霞珠为实验材料,分别在果实5%转色至成熟及果实100%转色至成熟两个生长期采用遮光率为50%（网1）、20%（网2）的遮阳网在不同时期对果树树体顶端进行遮光处理,利用高效液相色谱-质谱（HPLC-MS）法检测葡萄果实果皮中非花色苷酚的含量,并对非花色苷酚组分构成进行偏最小二乘法（PLS-DA）分析,探究葡萄果实不同生长发育阶段搭建遮阳网对葡萄果实非花色苷酚结构组分及含量的影响。结果显示在果实5%转色至完全成熟搭建遮光率50%、20%遮阳网处理（Q1、Q2）及果实100%转色至完全成熟期间搭建遮光率20%遮阳网处理（H2）非花色苷酚总量均显著高于对照组,运用PLS-DA分析可得到,遮光处理会影响葡萄果实中黄烷-3-醇、槲皮素类物质、杨梅酮类物质的积累。     

Variation of phenolic content in coconut oil extracted by two conventional methods

Phenolic compounds present in the nonsaponifiable fraction of coconut oil were analysed by high‐performance liquid chromatography with florescence detection. Mass spectra of the phenolic compounds were also obtained separately by LC–MS to confirm the presence of the phenolic compounds. Caffeic acid, p‐coumaric acid, ferulic acid and (+/?) catechin were observed in coconut oil. Phenolic acid fraction of the coconut oil prepared by boiling coconut milk (traditional coconut oil) was more complex compared with that of coconut oil prepared by pressing copra (commercial coconut oil). Total phenol content of traditional coconut oil was nearly seven times higher than that of commercial coconut oil (618 ± 46 vs. 91 ± 11 mg kg^?1), suggesting that the phenol content varies with the extraction method.     

不同葡萄砧木对矢富罗莎果肉酚类化合物含量的影响

矢富罗莎嫁接在7种不同的葡萄砧木上,检测其果肉中酚类化合物含量并与矢富罗莎自根苗果实中的酚类化合物含量进行比较。结果表明：矢富罗莎／520a和矢富罗莎／101—14MG组合可明显提高矢富罗莎果肉中的酚类化合物的含量,同时对砧木影响的复杂性及砧木选择和栽培的原则进行了讨论。     

饮料酒中挥发性酚类物质分析方法研究进展

挥发性酚类化合物是饮料酒的香味组成部分,对于酒的闻香、口味及稳定性等方面均具有重要的作用.有研究者认为,4-乙基苯酚(4-EP)和4-乙摹愈创木酚(4-EG)这2种挥发性酚,其在酒中的总浓度小于400μg/L时,为酒的风味贡献了辛香、烟香韵和革香韵;当其总浓度了大于620μg/L时,会使酒中产生腥异味,掩盖酒的香味.因此对酒中挥发性酚类物质的分析测定一直是研究的课题.目前饮料酒中挥发性酚的测定,主要采用各种样品前处理过程结合气相色谱或液相色谱的方法.随着先进仪器和设备的使用,样品前处理过程不断简化,饮料酒中挥发性酚的分析和测定正逐步向着简单、快速、准确度高的方向发展.文中综述了饮料酒中挥发性酚类物质分析方法的研究进展.     

Use of kinetic, Weibull and PLSR models to predict the retention of ascorbic acid, total phenols and antioxidant activity during storage of pasteurized pineapple juice

In this study, the usefulness of different mathematical models to predict the retention of ascorbic acid (AA), total phenols (TP) and DPPH radical scavenging activity (SA) of pasteurized pineapple juices during storage has been evaluated. The results indicate that first-order kinetic model provided the best prediction of the degradation of AA (MAE = 0.0059; MRE = 0.0117; MSE = 0.0001; R² = 0.9995) whereas Weibull model provided the less satisfactory prediction (MAE = 0.2387; MRE = 0.2911; MSE = 0.0769; R² = 0.9993). In addition, zero-order (MAE = 0.0016; MRE = 0.0017; MSE = 0.0000; R² = 0.9992) and first-order (MAE = 0.0027; MRE = 0.0029; MSE = 0.0000; R² = 0.9989) kinetic models are adequate models for application in the prediction of TP loss, and first-order kinetic (MAE = 0.0294; MRE = 0.0549; MSE = 0.0015; R² = 0.9845) and Weibull (MAE = 0.0533; MRE = 0.0881; MSE = 0.0044; R² = 0.9823) models are recommended to predict the change of SA. These results show that the behaviors of AA, TP and SA during storage of juices can be accurately described by different prediction models. Therefore, the selection of the most adequate model is of great importance to predict nutritional deterioration in food products during storage.     

Antioxidant potential of extracts from peels and stems of yellow-fleshed and white cassava varieties

This study focused on the exploration of the potentials of extracting antioxidants from peels and stems of yellow-fleshed and white cassava varieties. The effect of particle size (0.2 and 0.5 mm) and variety on the phenolic content and antioxidant activity was assessed. The peels of the yellow-fleshed cassava variety with a particle size of 0.2 mm showed the highest phenolic content with 681.5 GAE mg 100 g⁻¹ and antioxidant activity of 19% and 425 μM TE g⁻¹ dry matter using DPPH and FRAP assays respectively. The stems of the white cassava with a particle size of 0.2 mm exhibited high phenolic content (442.4 GAE mg 100 g⁻¹) and antioxidant activity of 12.8% and 234 μM TE g⁻¹, better than the stem of the yellow-fleshed cassava. These results indicate that phenolic and antioxidant extractions were influenced by variety, the plant parts and particle size for the antioxidant assays.     

Ruffed grouse feeding behavior and its relationship to secondary metabolites of quaking aspen flower buds

Quaking aspen (Populus tremuloides Michx.) staminate flower buds and the extended catkins are primary food resources for ruffed grouse (Bonasa umbellus). Winter feeding observations indicate that ruffed grouse select specific trees or clones of quaking aspen to feed in. Flower buds and catkins of quaking aspen were analyzed for secondary compounds (tannins, alkaloids, and phenolics) that might cause ruffed grouse to avoid trees with high levels of these compounds. Coniferyl benzoate, a compound that has not been previously found in quaking aspen, exists in significantly higher concentrations in buds from trees with no feeding history as compared to ruffed grouse feeding trees. Aspen catkins were also significantly lower in coniferyl benzoate than buds from the same tree. Ruffed grouse feeding preference was not related to the tannin or total phenolic levels found in buds or catkins. Buds from feeding trees had higher protein levels than trees with no feeding history; however, catkins did not differ from buds in protein concentration. The high use of extended catkins in the spring by ruffed grouse is probably due to a lower percentage of bud scale material in the catkin as opposed to the dormant bud. Bud scales contain almost all of the nontannin phenolics in catkins and dormant buds. A feeding strategy where bud scales are avoided may exist for other bird species that feed on quaking aspen. Dormant flower buds are significantly lower in protein-precipitable tannins than catkins and differ in secondary metabolite composition from other aspen foliage.Minnesota Agriculture Experiment Station Journal Series No. 16,953.     

Removal of organic contaminants in paper pulp effluents by AOPs: an economic study

The degradation of the organic content of a bleaching Kraft mill effluent was carried out using Advanced Oxidation Processes (AOPs). The study was focused on the identification of the AOP, or combination of AOPs, that showed the highest efficiency together with the lowest cost. Direct UV photolysis (UV), TiO₂ assisted‐photocatalysis (TiO₂/UV), Fenton, Fenton‐like, and photo‐Fenton reactions (Fe(II)/H₂O/UV), UV‐assisted ozonation (O₃/UV) and addition of Fe²⁺ and/or H₂O₂ to the TiO₂/UV and the O₃/UV systems, were used for the degradation of a conventional cellulose bleaching effluent. The effluent was characterized by the general parameters TOC, COD and color, and analyzed for chlorinated low molecular weight compounds using GC–MS. The costs of the systems per unit of TOC reduction were compared. Fenton, Fenton‐like and photo‐Fenton reactions achieved better levels of TOC degradation than photocatalysis and with lower cost's than photocatalytic treatments. Ozonation is an effective but rather expensive process. The use of UVA light, however, increased the effectiveness of ozonation with a significant decrease (>25%) in the operational cost. © 2002 Society of Chemical Industry